Fire detection system using random forest classification for image sequences of complex background

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Fire detection system using random forest classification for image sequences of complex background
Fire detection system using random
                 forest classification for image sequences
                 of complex background

                 Onecue Kim
                 Dong-Joong Kang

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Fire detection system using random forest classification for image sequences of complex background
Optical Engineering 52(6), 067202 (June 2013)

                Fire detection system using random forest classification
                for image sequences of complex background
                Onecue Kim                                                          Abstract. We present a fire alarm system based on image processing that
                Dong-Joong Kang                                                     detects fire accidents in various environments. To reduce false alarms that
                Pusan National University                                           frequently appeared in earlier systems, we combined image features
                Department of Control and Automation                                including color, motion, and blinking information. We specifically define
                Republic of Korea                                                   the color conditions of fires in hue, saturation and value, and RGB
                E-mail: djkang@pusan.ac.kr                                          color space. Fire features are represented as intensity variation, color
                                                                                    mean and variance, motion, and image differences. Moreover, blinking
                                                                                    fire features are modeled by using crossing patches. We propose an algo-
                                                                                    rithm that classifies patches into fire or nonfire areas by using random for-
                                                                                    est supervised learning. We design an embedded surveillance device
                                                                                    made with acrylonitrile butadiene styrene housing for stable fire detection
                                                                                    in outdoor environments. The experimental results show that our algorithm
                                                                                    works robustly in complex environments and is able to detect fires in real
                                                                                    time. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported
                                                                                    License. Distribution or reproduction of this work in whole or in part requires full attribution of the
                                                                                    original publication, including its DOI. [DOI: 10.1117/1.OE.52.6.067202]

                                                                                    Subject terms: fire detection; random forest; visual surveillance; embedded camera.
                                                                                    Paper 130413 received Mar. 17, 2013; revised manuscript received May 3, 2013;
                                                                                    accepted for publication May 13, 2013; published online Jun. 18, 2013.

                1 Introduction                                                                       environments. In most of the previous studies, it is necessary
                Conventional fire detection systems were designed to detect                          to determine whether an individual pixel is a fire or nonfire
                smoke, heat, and radiant energy from a fire using infrared,                          pixel. However, red objects that have a hue as fire are often
                optical, and ion sensors.1–3 However, these methods have                             mistaken for fire when determining each image pixel. In
                problems, namely, it is impossible to tell whether a fire is                         addition, moving lights, such as automobile headlamps, can
                occurring until smoke or flame spreads to the detection                              be mistaken for fires when using only motion information.
                range of sensors and detection takes a long time because                                 Therefore, we defined the color conditions of fire features
                a fire alarm is only issued after the flame’s influence exceeds                      in both hue, saturation and value (HSV) and RGB color
                                                                                                     space. The local features and motion information of fires
                a reference temperature or a set value. In addition, because
                                                                                                     were expressed using the mean, variance, and image differ-
                the detection range is restricted to the local position where
                                                                                                     ence. Moreover, temporally blinking properties were mod-
                sensors are installed, the need for numerous distributed sen-
                                                                                                     eled by using crossing patches so that it was possible to
                sors and installation increases the cost. On the other hand, a
                                                                                                     reduce the false detections described above. We defined
                fire detection system using image processing does not
                                                                                                     22 image features to classify patches into fire or nonfire
                require any additional costs, as it uses surveillance cameras                        areas by using a random-forest-supervised learning algo-
                already installed in public places, roads, and tunnels. Thus,                        rithm. The additive Markov chain was introduced to reduce
                fires can be quickly detected without having to wait until                           false alarms. Also, we designed an embedded surveillance
                flames spread to the sensors, and can be monitored over a                            device made from acrylonitrile butadiene styrene (ABS)
                broader range.                                                                       for stable fire detection in outdoor environments.
                    Early fire detection algorithms used rule-based color                                All modules, including image features extraction and fire
                models.4–6 They classify the image pixels as fire or not fire                        classification, are realized to test fire images of different con-
                by using the RGB, hue, saturation and intensity, and YCbCr                           ditions and verified to be robust in complex environments.
                color models. However, these methods have many false clas-
                sifications. For example, red clothes, moving cars, and lights
                will be recognized as fires because only color information                           2 Embedded Camera System
                was used. Han7 used color and motion information to present                          In general, to protect people from fires, fire surveillance sys-
                real-time fire detection. Töreyin et al.8 used temporal and                          tems require supervisors in monitoring rooms to observe vid-
                spatial wavelet analysis to separate the fire regions from                           eos transferred from CCTVs. Building a surveillance system
                sequential images. Although they presented good experi-                              requires considerable effort to install surveillance cameras,
                mental results, this approach is impractical in various envi-                        as many repeaters and wiring inside facilities are needed
                ronments due to many heuristic thresholds. Z. Teng9                                  to transfer videos to monitoring rooms, causing increased
                modeled the sequentially changing image pixel values by a                            installation costs. In addition, all images are concentrated
                hidden Markov model framework. Ko et al.10 applied a radial                          on servers in monitoring rooms and so the structure of server
                basis function kernel to two-class support vector machines.                          computers becomes complex. Therefore, we designed an
                This research that uses machine learning algorithms could                            embedded system with a built-in pan-tilt-zoom (PTZ) camera
                have an over-fitting problem and are not suitable for various                        to observe fire areas more effectively. The proposed system,

                Optical Engineering                                                        067202-1                                                              June 2013/Vol. 52(6)

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Fire detection system using random forest classification for image sequences of complex background
Kim and Kang: Fire detection system using random forest classification for image sequences. . .

                Fig. 1 Structure of fire detection system. (a) Fire detection system using commercial housing. (b) Customized system showing ABS resin housing
                and cooling conductor.

                which has a built-in embedded processor inside the camera,                        connector, as various foreign bodies in the form of particu-
                is capable of real-time image processing and consists of a                        late could otherwise enter the system.
                main camera that can monitor fires over a wide range and                              The whole operation of the fire detection system is
                a subcamera that can quickly zoom into fire areas when a                          depicted in Fig. 2. The main camera is a fixed type and
                fire occurs.                                                                      acquires raw images to detect fire while monitoring the
                    The early-designed device fixed each module by install-                       wide surveillance area. In addition, the installed industrial
                ing a fixed bracket inside a universal housing, as shown in                       digital camera is able to remove the noise generated in
                Fig. 1(a) and a subcamera below the housing. Due to heat                          the process of converting images from analog to digital.
                from the camera and embedded board, a prolonged operating                         This can simplify the system and permit control directly
                time rapidly raised the internal temperature of the housing. In                   by the program. A PTZ camera with maximum 10-magnifi-
                addition, the commercial housing suffered from the disad-                         cation was selected for the subcamera so that it is possible to
                vantages of heavy weight and expensive cost. In the second                        immediately magnify and transmit images of the area where
                system design, the cooling performance was improved by                            a fire has occurred. The images acquired from the main cam-
                projecting the cooling section of the embedded board out-                         era are processed in the built-in embedded board, and thus
                side, as shown in Fig. 1(b). This system reduced weight                           fire areas are detected. When the fire areas are detected, mag-
                by using an ABS resin housing and a digital output main                           nified images of fires are acquired from the subcamera. The
                camera. The ABS housing has the advantage of reducing                             acquired images from the subcamera are converted into dig-
                production costs because it can be produced in large quan-                        ital images by a frame grabber. Information, such as a gazing
                tities by injection molding. Protection from dust and mois-                       direction and scale, is transmitted by RS-422 communication
                ture was accomplished by using a rubber seal and waterproof                       to the main processor, for calculating PTZ motion data from

                                                                 Fig. 2 Operation process of the fire detection system.

                Optical Engineering                                                       067202-2                                           June 2013/Vol. 52(6)

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Fire detection system using random forest classification for image sequences of complex background
Kim and Kang: Fire detection system using random forest classification for image sequences. . .

                                                                                                               Fig. 5 Image Patch by block division of image.

                                                                                                  branching for lost data processing and handle both categori-
                                                                                                  cal and numerical data. In addition, it makes it unnecessary
                                                                                                  to normalize image features and easy to understand the
                                                                                                  importance of variables.
                                                                                                     First, in order to model the local features of fires, the input
                                                                                                  image is divided into small r × c patches (P), as shown in
                                                                                                  Fig. 5. We generate the color conditions, motion, and
                                                                                                  blink information of fires as features in the patch.

                Fig. 3 Magnified images by designating a fire detection area and
                using a PTZ camera.                                                               3.1 Modeling Fire Features
                                                                                                  In general, fires have specific colors in images. In this sec-
                                                                                                  tion, fire features were analyzed in RGB and HSV color
                the fire area detection of the main camera. Finally, the system                   space. For color features of fire in the RGB color space,
                transfers the fire location and magnified images of the fire                      it was observed that the R (red) color is larger than the thresh-
                area to the monitoring room. Figure 3 is a graphical user                         old value RTh and the R color value is the largest in the RGB
                interface screenshot of the fire monitoring system and an                         channel. Moreover, in the HSV color space, it is shown that
                image that detects fires and magnifies the detected areas.                        the H (hue) value of fire is 0 to 70 or 290 to 360. For exam-
                   Figure 4 shows CPU temperature change in both the cus-                         ple, the feature f 3 means the saturation will decrease with the
                tomized and commercial housing during 24 h. The measure-                          increasing red component, and thus the expression indicates
                ments were conducted after a detection algorithm operated                         that saturation will decrease downward to zero when the red
                for 1 h in each housing. It indicates that average improve-                       component increases toward the upmost value 255 (Refs. 12,
                ment of cooling performance is 22.017°C.                                          13). Therefore, the patch is likely to indicate a fire area when
                                                                                                  there are many pixels satisfying these fire conditions.
                3 Fire Detection Algorithm
                In previous studies,6–10 information from each pixel in the
                image was used to determine whether fires exist in the
                images. Alternatively, our paper proposes a method to model
                the local characteristics of fire, represented in sequential
                images based on patches of an input image, and to detect
                a fire area by using a supervised learning algorithm. The ran-
                dom forest showed a higher recognition rate than other
                machine learning algorithms.11 It can process substitution                                                  Fig. 6 Cross extractors.

                                                                                                       Table 1 Pseudo-code for the feature calculation of f 1 ∼ f 4 .

                                                                                                  Initiailize f 1 ∼ f 4

                                                                                                  For all pixels in a patch

                                                                                                  ifðPðr ; cÞR > R Th Þ; f 1 þ þ;

                                                                                                  ifðPðr ; cÞR > Pðr ; cÞG > Pðr ; cÞB Þ; f 2 þ þ;

                                                                                                  ifðPðr ; cÞS ≥ ð255 − Pðr ; cÞR Þ × S Th ∕R Th Þ; f 3 þ þ;

                Fig. 4 CPU Temperature changes in customized and commercial                       ifð290 ≤ Pðr ; cÞH ≤ 360 or 0 ≤ Pðr ; cÞH ≤ 70Þ; f 4 þ þ;
                housing during 24 h.

                Optical Engineering                                                       067202-3                                                        June 2013/Vol. 52(6)

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Fire detection system using random forest classification for image sequences of complex background
Kim and Kang: Fire detection system using random forest classification for image sequences. . .

                              Fig. 7 Feature extraction from a fire image. (a) Original image. (b) Color condition. (c) Motion information. (d) Crossing.

                Features (f i ) 1 to 4 show how many pixels satisfy each con-
                dition in the patch (Table 1).
                    The pixels in the fire areas are similar to specific colors
                such as red, yellow and white, and the deviation of colors is
                relatively uniform. Therefore, Features (f i ) 5 to 10 are
                defined by calculating the color mean and the variance for
                each RGB channel.

                PC ðr; cÞ ∼ NðμC ; σ 2C Þ;           C ∈ fR; G; Bg                      (1)

                f ½5: : : 10 ¼ fμR ; μG ; μB ; σ 2R ; σ 2G ; σ 2B g                    (2)

                   Additionally, it is observed that fires appear to blink in                                  Fig. 9 Learning and classifying process.
                sequential images. Using this, the number of blinks in a cer-
                tain area accumulated over 10 frames is defined as a feature.

                                                                                                  Fig. 10 Image patches used for learning. Fire sample (a), nonfire
                                              Fig. 8 Random forest.                               sample (b).

                Optical Engineering                                                       067202-4                                              June 2013/Vol. 52(6)

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Fire detection system using random forest classification for image sequences of complex background
Kim and Kang: Fire detection system using random forest classification for image sequences. . .

                              X                           X
                Diff ¼                     Iðpi Þ −                    Iðpi Þ           (3)       if½Pðc ¼ firejfÞ > Pðc ¼ NonFirejfÞthen Fire else NonFire
                          pi ∈black area              pi ∈white area
                                                                                                                                                                      (8)
                ifjDiff t − Diff t−1 j > threshold; then crossing occurs.               (4)          The whole process of learning and classification is
                                                                                                  described in Fig. 9. In order to learn fire, the input image
                   We defined three cross extractors to calculate the bright-                     is divided into the unit area. The 22 features defined in
                ness difference between the previous and subsequent patches                       the previous section are extracted from the divided images.
                as shown in Fig. 6. If the difference in brightness exceeds a                     When learners input the sample groups fc; fg; c ∈
                threshold value, then it is considered to be a crossing count.                    ffire; NonFireg into a learning machine, including classes
                Iðpi Þ in Eq. (3) is a brightness value at the pixel pi in the                    and features generated from the fire and nonfire images as
                image. In this paper, a total of nine features were generated                     shown in Fig. 10, the ensemble classifier and decision
                by using three different thresholds deciding the cross state in                   rule are generated by the random forest. When images are
                order to know the level of blinking.                                              captured in real-time, the random forest decides the fire
                                                                                                  and nonfire area by the decision rule.
                f ½11: : : .19 ¼ fcrossingith1 ; crossingith2 ; crossingith3 g;
                                                                                        (5)
                   i ∈ f1; 2; 3g.
                                                                                                  3.3 Decision of a Fire
                    Finally, this study used the feature that many motions                        When using the fire detection algorithm proposed in the pre-
                could be observed between previous and present frames in                          vious section, it is possible to distinguish between fire and
                fire areas. Automobile headlamps are known to generate
                strong noise, due to the dispersion of light when using
                                                                                                             Table 2 Descriptions of experimental movies.
                the common image difference between previous and sub-
                sequent frames. Therefore, motion pixels are defined as fea-
                tures after the removal of the noise by using the average                         Video sequence                         Description
                brightness of the three previous and subsequent frames.
                                      c  t
                                                                                                  Movie 1            People set fire to trees using equipment.
                                 Xr X                   t−1         t−2
                f ½20: : : 22 ¼          PC ðr; cÞ þ PC ðr; cÞ þ PC ðr; cÞ
                                                           3                                     Movie 2            There are trees burning at a close distance.
                                 r∈P c∈P
                                                                        
                                   Pt−1 ðr; cÞ þ Pt−2          t−3
                                                   C ðr; cÞ þ PC ðr; cÞ
                                                                                                 Movie 3            There is a fire in a narrow outside area. This
                                 − C                                    ;                                           movie is used for testing a small fire and a
                                                      3                                                              similar color in a scene.
                        C ∈ fR; G; Bg.                                                  (6)
                                                                                                  Movie 4            An entire forest is burning with smoke.
                   Figure 7 is the result that depicts the features defined
                                                                                                  Movie 5            There are automobile accidents occurring in
                above in an image. The image shown in the upper right indi-                                          the tunnel. This movie is used for confirming
                cates the area meeting the color conditions of Features 1 to 4.                                      whether pixels with the similar fire color and
                In addition, the image shown in the lower left represents the                                        motion are accurately classified in the scenes.
                motion of overlapping frames corresponding to features 20                                            There is no fire.
                to 22. An image shown in the lower right represents the
                crossing blocks between the previous and present frames.                          Movie 6            People create a fire and the equipment
                                                                                                                     extinguishes the fire inside a building.

                3.2 Learning RF and Classifying Fire Features                                     Movie 7            Firefighters set fire to a train in a tunnel.
                In order to classify the features defined in the previous sec-
                tion into fire and nonfire areas, this study used the random-                     Movie 8            There is fire occurring in an automobile and
                                                                                                                     a house in a city.
                forest supervised-learning method.14
                   The input feature (f) reaches the leaf node after following
                                                                                                  Movie 9            People set fire in a bucket and there are red
                the binary branch of decision tree (tn ). Each node (N) in the                                       objects such as a hat, backpack,
                ensembles t1 ðfÞ; t2 ðfÞ; : : : tn ðfÞ selects a feature minimizing                                  and a fire extinguisher.
                the Gini impurity (iðNÞ) in order to determine the feature and
                threshold value that can classify the feature into a suitable                     Movie 10           In the movie there is an ambulance blinking a
                class most effectively. Finally, probability [PðcjfÞ] of                                             siren. This movie is used for confirming whether
                each class is calculated by the summation of each leaf                                               pixels with the similar fire color and motion are
                                                                                                                     accurately classified in scenes. There is no fire.
                node probability, as shown in Fig. 8.
                         X                                                                        Movie 11           There are a lot of automobiles reducing speed
                iðNÞ ¼       Pðci Þ log Pðcj Þ.                                 (7)                                  at night with headlamps and tail lights on. This
                           j≠i                                                                                       movie is used for confirming whether pixels
                                                                                                                     with the similar fire color and motion are
                                                                                                                     accurately classified in scenes. There is no fire.
                   The assembly of each ensemble classifier generated in
                this manner is called a random forest. When given ensemble                        NOTE: The movies 1 ∼ 5 are available at http://signal.ee.bilkent.edu
                classifiers, feature vector F and class C, the feature vector is                  .tr/VisiFire/. The movies 9 and 11 were recorded by our embedded
                classified into fire as follows:                                                  system. The other movies were downloaded on YouTube.

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Fire detection system using random forest classification for image sequences of complex background
Kim and Kang: Fire detection system using random forest classification for image sequences. . .

                nonfire in various environments. However, false alarms                            give a higher weight to the fire’s appearance frequency or
                occurred in a couple of frames when an automotive head-                           continuity, and 0.7 is used in this experiment. z is a normal-
                lamp and taillight continuously intersected at night. In                          izing constant.
                order to solve this problem, the presence or absence of
                fires was finally determined by recording recent fire detec-                      B ¼ fx1 ; x2 ; : : : ; xN g;     xn ∈ f0; 1g                         (11)
                tion results during N frames and stochastically analyzing the
                state changes with the use of the additive Markov chain.15
                    An additive Markov chain is a theory that Xn is affected
                by previous sequential random variables (X n−1 ; X n−2 ; : : : )                                                                                     
                                                                                                                             1                         1
                and the sum of all the values becomes the final probability.                      fðxn ; xn−1 Þ ¼ ðαÞ              xn þ ð1 − αÞ              ðxn & xn−1 Þ ;
                                                                                                                            2N−n                      2N−n
                                                        X
                                                        N
                                                                                                              α ¼ ½0 ∼ 1.                                             (12)
                PðXn ¼ xn jX n−1 ; : : : ; X n−N Þ ¼          fðxn ; xn−1 Þ∕z           (9)
                                                        n¼1
                                                                                                      In this study, 2N number of cases is generated. The exe-
                                                                                                  cuting speed can be increased by the pre-calculated values
                z ¼ PðXn ¼ 0jX n−1 ; : : : ; X n−N Þ þ PðX n ¼ 1jX n−1 ; : : : ; X n−N Þ          with the Lookup Table.
                                                                                                      The detection results are determined during the accumu-
                                                                                      (10)        lated five frames, and the following rule is used for the final
                                                                                                  decision:
                   In this case, a memory function (fðÞ) is defined by the
                results of fire detection (B) during N frames as a binary num-
                ber. It represents the frequency of the fire detection and con-                   if PðXn ¼ FirejXn−1 ; : : : ; X n−5 Þ
                tinuity during N frames. In addition, the function is                                          > PðXn ¼ NonFirejX n−1 ; : : : ; Xn−5 Þ
                generated to give a higher weight to the variable close to
                the present state. α is a constant to determine whether to                                     × then Fire else NonFire.                               (13)

                           Fig. 11 Movie samples used for comparative experiments. (a) Movie 1. (b) Movie 2. (c) Movie 3. (d) Movie 4. (e) Movie 5.

                Optical Engineering                                                       067202-6                                                     June 2013/Vol. 52(6)

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Fire detection system using random forest classification for image sequences of complex background
Kim and Kang: Fire detection system using random forest classification for image sequences. . .

                4 Experiments                                                                     distributed according to their colors and motions. In selecting
                To learn fire features, 10,000 and 40,000 samples of a fire                       the samples of a nonfire area, learning was performed by
                and nonfire, respectively, were extracted from video images,                      dividing into several areas as follows: areas similar in
                such as in a tunnel, downtown, and mountain area. Numeri-                         color to fires without motion, areas different in color from
                cal type feature data were used for the training. The classifier                  fires with active motion, and areas completely different in
                was generated by random-forest supervised-learning.                               color from fires without motion. In such cases, it is desirable
                   When using the learning algorithm, the selection of not                        to select a relatively large number of nonfire samples,
                only features but also samples used for learning can have                         because many errors mistaking nonfire for fire occur
                a large impact on the classification results. For example,                        when the number of fire samples is relatively large.
                if most fire samples are red areas, the red areas will be                             In the first experiment as shown in Fig. 11, Movies 1 to 5
                detected well. However, it becomes difficult to detect the yel-                   were used to compare the fire detection algorithm proposed
                low and white areas. When learning only areas with active                         by Töreyin, Ko, and the method proposed in this paper.
                motion, it becomes difficult to detect the areas with the small                   Additionally, Movies 6 to 11 were used to perform experi-
                motion of a flame. Therefore, the fire samples used for learn-                    ments in more varied environments. The description of the
                ing should be selected so that the numbers are evenly                             images can be found in Table 2. True positive means that a

                Fig. 12 Images of fire detection results. (a) Movie 1. (b) Movie 2. (c) Movie 3. (d) Movie 4. (e) Movie 6. (f) Movie 7. (g) Movie 8. (h) Movie 9.

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Fire detection system using random forest classification for image sequences of complex background
Kim and Kang: Fire detection system using random forest classification for image sequences. . .

                                Fig. 13 Result of comparative experiments of Töreyin’s and Ko’s algorithms and detection rate (sum of TP þ TN).

                       Fig. 14 Movies used for analysis of detection rate. (a) Movie 6. (b) Movie 7. (c) Movie 8. (d) Movie 9. (e) Movie 10. (f) Movie 11.

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Fire detection system using random forest classification for image sequences of complex background
Kim and Kang: Fire detection system using random forest classification for image sequences. . .

                                                                                                  fire image is correctly determined as a fire, true negative
                                                                                                  means that a nonfire image is correctly determined as a non-
                                                                                                  fire, false positive means that a fire image is misjudged as a
                                                                                                  nonfire and false negative means a nonfire image is mis-
                                                                                                  judged as a fire.
                                                                                                      Overall results of the first experiment are shown in
                                                                                                  Figs. 12 and 13. The method proposed in this study
                                                                                                  shows a higher detection rate than the other two methods.
                                                                                                  In this case, the detection rate is the sum of the values of
                                                                                                  true positive and true negative. In Movie 1, it was not pos-
                                                                                                  sible to consider the motion information properly because
                                                                                                  the frame rate of the video was lower than other images.
                                                                                                  In Movie 3, the detection rate was lower than other images
                                                                                                  because the size of the fire area was smaller than other
                                                                                                  patches used in the experiment. Furthermore, in Movie 5,
                                                                                                  the false alarm shown in the method by Ko did not occur
                                                                                                  in the experiment with the proposed method.
                                                                                                      As depicted in Fig. 14, the second experiment was per-
                                                                                                  formed by using fires in tunnels, inside buildings and auto-
                                                                                                  mobiles, with a blinking ambulance light, continuously
                                                                                                  passing automobile headlamps, and tail lights likely to be
                                                                                                  mistaken for fires. As shown in Fig. 15, the detection rate
                                                                                                  was an average of 96.45% and we could reduce the average
                                                                                                  of false negative rate from 2.1% to 1.31% when applying the
                                                                                                  additive Markov chain. However, as shown in Fig. 16(a) and
                                                                                                  16(b), false positives were shown because the fire area was
                                                                                                  small at the moment when the fire was extinguished in Movie
                                                                                                  6 and as the fire started in Movie 9. Depicted in Fig. 16(c)
                                                                                                  and 16(d), the false negatives occurred because the color,
                                                                                                  motion and crossing feature were similar to fires. Movie 9
                                                                                                  demonstrated whether the classifier works well when expos-
                Fig. 15 Result of detection rate performed in various environments.
                (a) Before applying additive Markov chain. (b) After applying additive            ing a bag, hat, and fire extinguisher similar in color to flames
                Markov chain.                                                                     in the image. The results showed that it worked well even
                                                                                                  when moving the hat and bag. Although there were many
                                                                                                  areas that had values similar to the fire features defined
                                                                                                  above in Movies 10 and 11, the classifier could work
                                                                                                  well because each of the feature values were relatively small.

                                  Fig. 16 Cases of false positive: (a) Movie 6, (b) Movie 9. Cases of false negative: (c) Movie 9, (d) Movie 11.

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Kim and Kang: Fire detection system using random forest classification for image sequences. . .

                                                                                                  and Technology (Nos 2011-0027213 and 2011-0017228)
                                                                                                  and this work was partly supported by the Human
                                                                                                  Resources Development program (No. 20114010203080)
                                                                                                  of the Korea Institute of Energy Technology Evaluation
                                                                                                  and Planning (KETEP) grant funded by the Korea government
                                                                                                  Ministry of Trade, Industry and Energy.

                                                                                                  References
                                                                                                   1. S. Verstockt et al., “Multi-sensor fire detection by fusing visual and non-
                                                                                                      visual flame features,” in Image Sig. Process., pp. 333–341, Springer,
                                                                                                      Berlin, Heidelberg (2010).
                                                                                                   2. S. Bhattacharjee et al., “Wireless sensor network-based fire detection,
                                                                                                      alarming, monitoring and prevention system for Bord-and-Pillar coal
                       Fig. 17 Variable importance of learned random forest.                          mines,” J. Syst. Softw. 85(3) 571–581 (2012).
                                                                                                   3. I. Bosch, S. Gómez, and L. Vergara, “A ground system for early forest
                                                                                                      fire detection based on infrared signal processing,” Int. J. Rem. Sens.
                    It is possible to recognize variable importance in the                            32(17) 4857–4870 (2011).
                                                                                                   4. T.-H. Chen, P.-H. Wu, and Y.-C. Chiou, “An early fire-detection method
                learning process when using random-forest supervised-                                 based on image processing,” in Image Processing, 2004. ICIP'04. 2004
                learning. Figure 17 shows that the importance of 22 features                          International Conference on, Vol. 3, pp. 1707–1710, IEEE (2004).
                                                                                                   5. T. Çelik and H. Demirel, “Fire detection in video sequences using a
                is evenly distributed. In this case, Features 5 and 7 are rel-                        generic color model,” Fire Safety J. 44(2) 147–158 (2009).
                atively high because the classifier frequently used the mean                       6. W.-B. Horng, J.-W. Peng, and C.-Y. Chen, “A new image-based real-
                value of red and blue color channels during the training. The                         time flame detection method using color analysis,” in Networking,
                                                                                                      Sensing and Control, 2005. Proceedings. 2005 IEEE, pp. 100–105,
                rate of features (1 ∼ 10) related to the fire color are 51.2%. It                     IEEE (2005).
                means that the color features are more effective than the                          7. D. Han and B. Lee, “Flame and smoke detection method for early
                motion and crossing features (11 ∼ 22). However, the motion                           real-time detection of a tunnel fire,” Fire Safety J. 44(7) 951–961 (2009).
                                                                                                   8. B. Töreyin et al., “Computer vision based method for real-time fire and
                and crossing features perform the role of the fire features                           flame detection,” Patt. Recog. Lett. 27(1) 49–58 (2006).
                very well. It works to prevent miss-classifications when sim-                      9. Z. Teng, J.-H. Kim, and D.-J. Kang, “Fire detection based on hidden
                                                                                                      Markov models,” Intl. J. Contr. Autom. Syst. 8(4) 822–830 (2010).
                ilar colors, such as automobile headlamps and red hats,                           10. B. C. Ko, K.-H. Cheong, and J.-Y. Nam, “Fire detection based on vision
                appear in scenes. In the color features, a contribution of                            sensor and support vector machines,” Fire Safety J. 44(3), 322–329
                the RGB channel values (5 ∼ 7) is higher than the color con-                          (2009).
                                                                                                  11. R. Caruana, N. Karampatziakis, and A. Yessenalina, “An empirical
                ditions (1 ∼ 4). In the crossing features (11 ∼ 19), crossing                         evaluation of supervised learning in high dimensions,” in
                features for small threshold (11 ∼ 13) have more influences                           Proceedings of the 25th international conference on Machine learning,
                on detecting fires.                                                                   pp. 96–103, ACM (2008).
                                                                                                  12. T.-H. Chen, P.-H. Wu, and Y.-C. Chiou, “An early fire-detection method
                    The algorithm could process approximately 30 frames of                            based on image processing,” in Image Processing, 2004. ICIP'04. 2004
                320 × 240 image in Core 2 Duo 2.00 Ghz at our embedded                                International Conference on, Vol. 3, pp. 1707–1710, IEEE (2004).
                                                                                                  13. T.-H. Chen, C.-L. Kao, and S.-M. Chang, “An intelligent real-time fire-
                system.                                                                               detection method based on video processing,” in Security Technology,
                                                                                                      2003. Proceedings. IEEE 37th Annual 2003 International Carnahan
                5 Conclusions                                                                         Conference on, pp. 104–111, IEEE (2003).
                                                                                                  14. L. Breiman, “Random forests,” Mach. Learn. 45(1) 5–32 (2001).
                In this paper, a fire detection system with the built-in                          15. S. S. Melnyk, O. V. Usatenko, and V. A. Yampol’Skii, “Memory func-
                                                                                                      tions of the additive Markov chains: applications to complex dynamic
                embedded processor, the main camera, and the PTZ camera                               systems,” Phys. Stat. Mech. Appl. 361(2), 405–415 (2006).
                was designed to perform fire surveillance in various environ-
                ments. In addition, fire features were modeled by color,
                                                                                                                             Onecue Kim received a BS in computer sci-
                motion, and crossing features. This paper proposed an algo-                                                  ence from Tongmyong University, Korea, in
                rithm that could detect fires precisely by using the random                                                  2008. He is now a postgraduate and doctoral
                forest classifier, making it possible to reduce the false alarms                                             student in mechanical engineering at Pusan
                that occurred in previous studies resulting from the complex                                                 National University, Korea. His current
                                                                                                                             research interests are visual surveillance,
                background. We used an additive Markov chain method for a                                                    machine vision, robots, and pattern recogni-
                robust fire detection algorithm. The performances of this                                                    tion.
                method were verified by comparative experiments with
                other methods in various environments. The proposed fire
                detection system can detect fires with high reliability in pub-
                lic places, such as buildings, roads and tunnels. Also, it min-                                             Dong-Joong Kang received a BS in preci-
                imizes casualties and property damages by early fire                                                        sion engineering from Pusan National Uni-
                detection. In addition, the automatic surveillance system                                                   versity in 1988 and a PhD in automation
                                                                                                                            and design engineering at KAIST (Korea
                can reduce facility maintenance costs by reducing the num-                                                  Advanced Institute of Science and Technol-
                ber of monitoring personnel and the fatigue level of the                                                    ogy) in 1998. From 1997 to 1999, he was
                supervisor. Therefore, our system contributes to increased                                                  a research engineer at Samsung Advanced
                safety in public places because potential fires can be moni-                                                Institute of Technology (SAIT) and from
                                                                                                                            2000 to 2005 he was an assistant professor
                tored 24 h a day.                                                                                           in the mechatronics engineering department
                                                                                                                            at Tongmyong University. He has been an
                Acknowledgments                                                                   associate professor at the School of Mechanical Engineering at
                                                                                                  Pusan National University since 2006 and associate editor of the
                This work was supported by the Basic Science Research                             International Journal of Control, Automation, and Systems since
                Program through the National Research Foundation of                               2007. His current research interests include visual surveillance, intel-
                Korea (NRF) funded by the Ministry of Education, Science                          ligent vehicles/robotics, and machine vision.

                Optical Engineering                                                       067202-10                                                      June 2013/Vol. 52(6)

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